I want to create a web application that works similiar to a file explorer like dolphin, where you can have several tabs that contain tables to display some files. But when resizing the column width it comes to an error. To do so I create a page using this code

and see an NullPointerException thrown in SortingFilteringRowsRenderer.updateAttribute(). However when refreshing the page after switching tabs no exception is thrown.

Is there something wrong with my code?

updateAttribute() is called from ExtendedDataTableRenderer.updateWidthOfColumns(). When I observe this method I can see that 'widthEntry' carries an id. I inspected the ids in both cases, when the application is running without showing an error (i.e. with refreshing) in comparison to the other case with error and found that there must be the problem.

In case the exception will be thrown its still the id that corresponds to the previously selected tab.

No, it's the same with the current Snapshot. Even setting sortBy and sortOrder for each column does not help. Strangely enough, selecting an entry in each table seems to help for one or two tabswitches, but then the error will occur again.

You could set a breakpoint into SortingFilteringRowsRenderer.java (line 135) or follow the call hierarchy:

Now I looked up the POST-request using firebug. After resizing the column I can find an integer succeeded by 'px' there. The next id preceeding this width is the id that is shown in 'widthEntry' in the method 'updateWidthOfColumns()'.

So when selecting an entry in each tables seems to help I guess that an variable update on the client happens too late.